The present invention relates to connectors for installation on a terminal end of a coaxial cable as used, for example, in CATV applications by radial compression of the cable by a deformable body portion of the connector. More specifically, the invention relates to compression-type connectors wherein the number of parts is reduced and manner of effecting compression is different from conventional, prior art connectors of this type.
A common type of connector installed on a terminal end of a coaxial cable includes elements known as a post, a nut, a body and a compression ring. The post includes a hollow stem integrally joined at one end to a flange. The nut is rotatably secured to the post, typically at or near the junction of the stem and flange, and the body surrounds the stem with a first portion, near the nut, in frictional engagement therewith and a second portion in outwardly spaced relation thereto. The compression ring, a hollow, substantially cylindrical member, is initially maintained in engagement with the body by one end of the ring encircling the end of the body remote from the nut. The end of the coaxial cable is prepared by stripping away certain layers thereof at specified distances from the end of the central conductor. After the cable is xe2x80x9cpreppedxe2x80x9d the connector is installed by inserting the cable axially into the connector with the stem of the connector post being forced between the outer layer of conducting material and the woven mesh metallic shielding layer. The shielding layer and the outer dielectric layer are in the initially open, annular space between the stem and inner surface of the body. Installation is completed by axial movement of the compression ring over the body with tapered surfaces on one or both of these members causing radial compression of the body into tight, frictional engagement with the outer surface of the coaxial cable.
The prior art includes, of course, a wide variety of styles and configurations of compression connectors of this general type. A feature common to radial compression connectors, however, is the separate fabrication of the body and compression ring which provide the means of frictionally engaging the connector with the cable. A variation of this design is disclosed in U.S. Pat. No. 5,525,076 of Down wherein the connector body includes one or more grooves extending into and around its outer surface. As the body is axially compressed, a portion of the body wall at the groove(s) is forced radially inwardly, into the outer dielectric layer of the coaxial cable. This forms a moisture barrier around the surface of the cable and mechanically locks the connector and cable, but does not radially compress the body into tight frictional engagement with the cable in the manner of the prior art connectors alluded to above and the present invention.
It is a principle object of the present invention to provide a novel and improved coaxial cable connector of the radial compression type which requires fewer parts than typical prior art connectors of the same general type, thereby offering advantages normally associated with a reduction in part count of multi-element devices.
It is a further object to provide a connector which is mounted to an end portion of a coaxial cable by a novel method of operation.
It is another object to provide novel and improved means for mounting a connector to the end of a coaxial cable.
Other objects will in part be obvious and will in part appear hereinafter.
In furtherance of the foregoing objects, the invention contemplates a connector having an essentially conventional post and nut in combination with a novel body. The post has the usual, integral flange and stem portions and the nut is rotatably engaged with the post at the flanged end. The hollow body includes a first portion extending axially from a first end and having an inner diameter substantially corresponding to the outer diameter of the post stem, a second portion extending axially from the first portion and having a larger inner diameter, and a third portion extending axially from the second portion to a second end. The three portions are integrally formed as a single, molded part. In a first disclosed embodiment, the third portion is connected to the second portion by a wall section of reduced thickness. The third portion is of the same inner diameter as the second portion and tapers to a larger outer diameter from the position of smallest wall thickness toward the second end of the body. When the connector is installed on the cable, the stem extends between the metal shielding layer of the cable and the outer conducting layer in the usual manner with these two layers positioned in the space between the outside of the stem and inside of the second body portion. When an axial force is applied (by an appropriate tool) to the third body portion, tending to move it in the direction of the first portion, the wall fractures at the section of smallest thickness, allowing the third section to be forced between the second section and the outer surface of the coaxial cable. The tapered surface on the third section is wedged between the second section and the cable surface, thereby radially compressing the cable and causing tight frictional engagement of the connector and cable.
In a second embodiment, the third section of the body has two annular areas of reduced cross section, axially spaced from one another. The thickness of these sections is such, relative to the type and characteristics of the material from which the body is fabricated, that as axial force is applied to the third section, tending to move it in the direction of the second section, that the wall folds at both areas of reduced cross section. Thus, rather than fracturing the body wall, as in the first embodiment, the body remains in a single part, but with folded layers of the third body portion between the inner surface of the second body portion and the outer surface of the cable, producing tight frictional engagement of the connector and the cable.
The features of the invention generally described above will be more readily apparent and fully appreciated from the following detailed description, taken in conjunction with the accompanying drawings.